问题
I am using a javascript validator which will let me build custom validation based on regexp
From their website: regexp=^[A-Za-z]{1,20}$ allow up to 20 alphabetic characters.
This will return an error if the entered data in the input field is outside this scope.
What I need is the string that will trigger an error for the inputfield if the value has an asterix as the first character.
I can make it trigger the opposite (an error if the first character is NOT an asterix) with:
regexp=[\u002A]
Heeeeelp please :-D
回答1:
How about:
^[^\*]
Which matches any input that does not start with an asterisk; judging from the example regex, any input which does not match the regex will be cause a validation error, so with the double negative you should get the behaviour you want :-)
Explanation of my regex:
- The first
^means "at the start of the string" - The
[...]construct is a character class, which matches a single character among the ones enclosed within the brackets - The
^in the beginning of the character class means "negate the character class", i.e. match any character that's not one of the ones listed - The
\*means a literal*;*has a special meaning in regular expressions, so I've escaped it with a backslash. As Rob has pointed out in the comments, it's not strictly necessary to escape (most) special characters within a character class
回答2:
How about ^[^\*].+.
Broken down:
^= start of string.[^\*]= any one character not the '*'..+= any other character at least once.
回答3:
You can invert character class by using ^ after [
regexp=[^\u002A]
来源：https://stackoverflow.com/questions/5293859/javascript-regexp-only-if-first-character-is-not-an-asterisk